Adding idasanutlin to cytarabine does not improve overall survival (OS) in patients with relapsed or refractory acute myeloid leukemia (AML), according to research published in Blood Advances.

However, idasanutlin plus cytarabine improved the overall response rate (ORR) when compared with cytarabine alone.

Researchers explored the effects of adding idasanutlin — a selective small-molecule MDM2 antagonist — to cytarabine in the phase 3 MIRROS study ( Identifier: NCT02545283).

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Overall, 355 patients were enrolled to the intent-to-treat population. Of these, 232 were randomly assigned to the idasanutlin-cytarabine group, and 123 patients were assigned to receive cytarabine with placebo. All patients had wild-type TP53.

In the idasanutlin and placebo groups, the median ages were 63 and 62 years, respectively, 52.2% and 54.5% of patients were men, and 49.8% and 52.8% of patients were in first relapse at screening.

The median OS was 8.3 months in the idasanutlin arm and 9.1 months in the placebo arm (hazard ratio, 1.08; P =.58). The ORR was 38.8% and 22%, respectively (odds ratio [OR], 2.25; 95% CI, 1.36-3.72). The complete response rate was 20.3% and 17.1%, respectively (odds ratio [OR], 1.23; 95% CI, 0.7-2.18).

Common adverse events (in the idasanutlin and placebo arms, respectively) were diarrhea (87.0% vs 32.9%), febrile neutropenia (52.8% vs 49.3%), and nausea (52.5% vs 31.5%).

Despite the improved ORR in the idasanutlin arm, the study authors concluded that adding idasanutlin to cytarabine in relapsed or refractory AML is unlikely to improve clinical outcomes. They noted, however, that “further research is needed to clarify whether MDM2 inhibitors such as idasanutlin may still have a potential role in earlier-stage AML or other cancer settings.”

Disclosures: This research was sponsored by Hoffmann-La Roche. The study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of authors’ disclosures. 


Konopleva MY, Röllig C, Cavenagh J, et al. Idasanutlin plus cytarabine in relapsed or refractory acute myeloid leukemia: results of the MIRROS trial. Blood Adv. 2022;6(14):4147-4156. doi:10.1182/bloodadvances.2021006303

This article originally appeared on Hematology Advisor